The objective of the proposed research is the further investigation of the noradrenergic cyclic AMP generating system in limbic structures of the brain, particularly as it relates to norepinephrine receptor function and its modification by major psychotropic drugs such as antipsychotic and antidepressant agents. Emphasis is placed a) on the development of a ligand for the norepinephrine receptor that is not beta in nature b) on the ontogenetic development of the norepinephrine receptor system in limbic structures and c) on molecular mechanisms of receptor regulations under conditions of supersensitivity (e.g. reserpine) and/or subsensitivity (e.g. tricyclic antidepressants).